At the present, for the manufacture of construction elements of this type, whether they be or plaster of cement, individual molds are used with articulated walls permitting the removal of the squares from the mold. Dual molds are also known. These single or dual molds permit neither a high production rate nor an accelerated automation cycle of manufacture.
There are also known multiple-mold machines in which the stripping conditions are not positively controlled so as not only to prevent mechanized or automated handling after stripping but also to make a considerable percentage of waste inevitable.
Moreover these molds cannot be closed with proper tightness difficulties encountered on closure inevitably slow down production considerably.